The present invention relates to a beater amplitude adjustment mechanism for a drum beater pedal. A pedal operated drum beater includes a beater with a beater head that is swung from a rest position to bang a drum head. The amplitude of that swing is determined by the distance of the beater head from the drum head before the beater head swings. The invention concerns setting the starting point of the swing of the beater head.
FIGS. 5 through 7 show a conventional beater mechanism for beating the head of bass drum. A drum pedal device 90 has a base 91. Supports 92 are erected on both sides of the base 91. A horizontal beater rotary shaft 94 is freely rotatable in ball bearings 93 provided toward the tops of the supports 92.
Approximately at the center of the rotary shaft 94, there are a beater installation member 110 and next to it a wheel 120 which both rotate integrally with each other. The beater 115 is comprised of a shaft with a beater head at its end, and that shaft is fixed to the beater installation member 110 by an attachment screw.
The wheel 120 comprises a sprocket or at least a partial sprocket on its outer periphery. One end of the chain is fixed to the wheel 120 and trained on the sprocket teeth. The other end of the chain 121 is connected to the tip of a foot pedal 95. As the foot pedal 92 is stepped on by a performer, as indicated by arrow A in FIG. 5, the chain 121 is pulled down. This rotates the wheel 120 in turn rotates the beater installation member 110 which causes the head of the beater 115 to strike the drum surface D.
A cam 100 is fixed at the end of the rotary shaft 94 by a screw 101. As shown in FIG. 5, the cam 100 has approximately the shape of a fan. In FIG. 7, a bearing hole 102 formed at the pivot of the fan shaped cam receives the rotary shaft 94. A plurality of roller installation holes 103 are provided at spaced intervals around the periphery of the cam. A roller installation bolt 104 is screwed into one of the roller installation holes 103. The hole 103 selected to receive the bolt 104 determines the initial rotary orientation of the cam and the start of the swing of the beater 115, as described below. A roller 105 is inserted into the roller installation bolt 104. The roller 105 supports a hanging ring 106.
The top of a tension spring 107 is supported on the tip of the hanging ring 106. The lower end of the spring 107 is supported to a lower bracket 109 which is outside the support 92. The force of the spring 107 pulls down on the ring 106 and the bolt 104 and automatically returns the beater 115 to its original position away from the drum head. The hole 103 selected determines the rotative orientation of the cam 100, the shaft 94 and the beater 115 at the start position. An adjusting bolt 108 adjusts the tension of the spring 107. A known clamp 130 holds the base on the drum hoop.
The amplitude of the swing of the beater 115 is established by tilting the incline of the beater installation member 110, thereby changing the distance between the head of the beater 115 and the drum surface D. This is done by selecting one of the positions defined by the plurality of installation holes 103 in the cam 100 for changing the incline of the cam.
The conventional mechanism determines the amplitude of swing of the beater stepwise by the position based on the separated roller installation holes 103. This makes difficult a delicate amplitude adjustment according to the desire or performance style of the performer. In addition, adjustment of the beater amplitude position has been troublesome, since it has been necessary to remove the roller installation bolt 104 each time the spring 107 is replaced.
In view of the above-described situation, the present inventor proposed, in Japanese Utility Model Application Hei 3-38099, a beater amplitude adjusting mechanism for a drum pedal, wherein a cam is fixed at the end of a beater rotary shaft which is freely rotatably supported on a support. The spring is adjusted through the roller on the cam through an arc-shaped roller installation groove in the cam having the beater rotary shaft as the center, which adjustably fixes the roller.
The above design enables creation of delicate sound expressions, because the amplitude of the beater swing can be adjusted over a continuous range and without the presence of a step by changing the rotary position of the beater rotary shaft as compared with the spring by employing a cam.
With either of the aforementioned beater amplitude adjust mechanism because both of the beater installation member and the wheel are fixed to the beater rotary shaft, the wheel on which the chain is trained rotates as the rotary position of the beater rotary shaft is changed for adjusting beater amplitude. The rotation of the wheel causes the height position of the pedal plate to also change, thereby creating inconvenience to the performer.